1. Technical Field
The present invention relates in general to improved interior surface finishing, and in particular to an automated apparatus for finishing interior surfaces such as drywall, acoustic, and painted surfaces.
2. Description of the Prior Art
Wallboard or drywall has become the dominant material in the production of interior building partitions. Interior building partitions typically comprise a studwall of vertical support members or studs that are spaced apart from each other in a parallel arrangement. The studs are used to support preformed panels or wallboards that are usually attached to the studwall with fasteners. A joint exists between adjacent ones of the the abutted wallboards.
In order to provide a continuous flat surface appearance to the wall, it is necessary to apply a finish to the joint between the adjacent panels. Finishing typically requires the build-up of multiple layers of a mastic material or joint compound that is commonly referred to as mud. Mud is a paste-like substance that is formed by mixing a powdery compound with water. The blending of the joint compound into the panel surface forms the desired flat and contiguous wall surface. The build-up of mud in the joint area or xe2x80x9cfloatingxe2x80x9d comprises the application of a first layer of mud and the embedding of a wallboard tape such as paper or fiberglass tape in the first layer. Finally, one or two more layers of mud are applied on top of the first layer/tape to complete the joint. The finishing of the joints is a time consuming and labor intensive process, since it is generally necessary to wait 24 hours between each application of mud in order to allow each layer to dry. In addition, it is generally necessary to sand the joint area so as to produce a finish that matches the remainder of the wallboards.
It is convenient to use a container for the mud which may or may not include means for supporting a roll of tape. Combination mud and tape devices guide the tape through the mud and dispense it from the container at the desired length with the tape coated in the mud. A number of devices have been devised in attempts to more efficiently and effectively dispense mud during the drywalling process. Some devices are pressurized to dispense the mud, while others require traditional manual application. Unfortunately, most prior art designs have not been fully accepted by the construction trade. In particular, air pressurized systems have been marginal at best as there is significant time lag during dispensing, and a potentially uneven application.
The application of drywall mud can also require large pieces of equipment including a mud tank that is hauled on trucks to the work site. The equipment is routinely left outside the structure being drywalled. After each day""s use, the equipment, particularly the mud tank, must be cleaned with pressurized water. This operation usually involves another piece of equipment.
Accordingly, a need exists for an automated apparatus for interior finishing, such as a drywall compound feeding device, that provides a steady and closely controlled flow rate of mixed material through an application fixture. Another need exists for an automated, positive displacement device, such as a mud feeding device, that has negligible hesitation or lag time between the initial release of material through the applicator and the time at which the material reaches its steady state flow rate. In addition, a need exists for a finishing apparatus that does not require clean-up of the apparatus and tools, and which is less cumbersome and more portable.
One embodiment of an automated device for finishing interiors utilizes an apparatus having an upper section for material mixing purposes, and a lower section for material conveying purposes. The upper section has a large basin with a mixing compartment and a separate washing/tool storage compartment. Each compartment has a hinged lid that forms an air-tight seal. The storage compartment has a hose with a spray nozzle for dispensing a pressurized spray of water. The mixing compartment has a mixer shaft with a modified ribbon auger for mixing compound with water dispensed from jets located in the mixing compartment. The lower section of the apparatus contains a motor for driving a progressive cavity pump, which receives mixed material from the mixing compartment. A pair of water pumps are also mounted to the lower section and provide pressurized water to the upper compartments from a water tank. The pump delivers a smooth and uniform supply of material through an external supply hose.
The apparatus is used as one component of an overall automated interior finishing system and method for completing surface finishes. For example, one end of the supply hose is connected to the outlet end of the pump for delivering mixed material to a hand tool at the opposite end, such as a flat taper. Many other combinations of tools and components are possible for finishing surfaces, depending upon the particular application required. In another embodiment, the automated interior finish apparatus has two pumping systems that allow two operators to simultaneously use the device. In yet another embodiment, the automated interior finish apparatus has a single compartment for mixing, clean-up, and tool storage. Each of these versions is capable of being partially disassembled or broken down into two separate, lighter pieces with four easy steps.
The foregoing and other objects and advantages of the present invention will be apparent to those skilled in the art, in view of the following detailed description of the preferred embodiment of the present invention, taken in conjunction with the appended claims and the accompanying drawings.